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AWS Migration - Database Migration Service

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• AWS Migration - Database Migration Service
  • Database Migration Service
    • Sources and Targets
    • Schema Conversion Tool (SCT)
    • Continuous Replication
    • Multi-AZ Deployment
    • Hands-on
  • Use Case: RDS \& Aurora MySQL Migration
    • RDS MySQL to Aurora MySQL
    • External MySQL to Aurora MySQL
    • DMS: Up and running
  • Use Case: RDS \& Aurora PostgreSQL Migrations
    • RDS PostgreSQL to Aurora PostgreSQL
    • External PostgreSQL to Aurora PostgreSQL
    • DMS: up and running

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Database Migration Service

• Database Migration Service

  • Used to quickly and securely migrate databases to AWS, resilient, self healing

• Feature:

  • The source database remains available during the migration
  • Continuous Data Replication using CDC(change data capture)
  • You must create an EC2 instance to perform the replication tasks

• Supports:

  • Homogeneous migrations:
    • ex Oracle to Oracle
  • Heterogeneous migrations:
    • ex Microsoft SQL Server to Aurora

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Sources and Targets

• SOURCES:

  • On-Premises and EC2 instances databases:
    • Oracle, MS SQL Server, MySQL, MariaDB, PostgreSQL, MongoDB, SAP, DB2
  • Azure:
    • Azure SQL Database
  • Amazon RDS:
    • all including Aurora
  • Amazon S3
  • DocumentDB

• TARGETS:

  • On-Premises and EC2 instances databases:
    • Oracle, MS SQL Server, MySQL, MariaDB, PostgreSQL, SAP
  • Amazon RDS
  • Redshift, DynamoDB, S3
  • OpenSearch Service
  • Kinesis Data Streams
  • Apache Kafka
  • DocumentDB & Amazon Neptune
  • Redis & Babelfish

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Schema Conversion Tool (SCT)

• Schema Conversion Tool (SCT)

  • Convert your Database’s Schema from one engine to another when DB engines are different.
  • Example OLTP: (SQL Server or Oracle) to MySQL, PostgreSQL, Aurora
  • Example OLAP: (Teradata or Oracle) to Amazon Redshift

• Prefer compute-intensive instances to optimize data conversions

• You do not need to use SCT if you are migrating the same DB engine

  • Ex: On-Premise PostgreSQL => RDS PostgreSQL
  • The DB engine is still PostgreSQL (RDS is the platform)

• Sample:

  • You have an on-premises Oracle database that you want to migrate to AWS, specifically to Amazon Aurora. How would you do the migration?
    • AWS SCT to convert db schema, AWS DMS to migrate the data.

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Continuous Replication

• first, SCT
• then migration

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Multi-AZ Deployment

• When Multi-AZ Enabled, DMS provisions and maintains a synchronously stand replica in a different AZ

• Advantages:

  • Provides Data Redundancy
  • Eliminates I/O freezes
  • Minimizes latency spikes

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Hands-on

• Create Replication Instance

• Create endpoins

• Create migration task

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Use Case: RDS & Aurora MySQL Migration

RDS MySQL to Aurora MySQL

• 1. DB Snapshots from RDS MySQL restored as MySQL Aurora DB
     • downtime

• 1. Create an Aurora Read Replica from your RDS MySQL, and when the replication lag is 0, promote it as its own DB cluster
  • continuous, can take time and cost $

• Sample:
  • A company is using RDS for MySQL as their main database but, lately they have been facing issues in managing the database, performance issues, and the scalability. And they have decided to use Aurora for MySQL instead for better performance, less complexity and less administrative tasks required. What is the best way and most cost-effective way to migrate from RDS for MySQL to Aurora for MySQL?
    • create a snapshot from RDS and restore to Aurora

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External MySQL to Aurora MySQL

• Option 1:

  • Use Percona XtraBackup to create a file backup in Amazon S3
  • Create an Aurora MySQL DB from Amazon S3

• Option 2:

  • Create an Aurora MySQL DB
  • Use the mysql dump utility to migrate MySQL into Aurora
    • slower than S3 method

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DMS: Up and running

• Use DMS if both databases are up and running
  • do continious replication between 2 db.

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Use Case: RDS & Aurora PostgreSQL Migrations

RDS PostgreSQL to Aurora PostgreSQL

• Option 1: DB Snapshots from RDS PostgreSQL restored as PostgreSQL Aurora DB

  • Downtime

• Option 2: Create an Aurora Read Replica from your RDS PostgreSQL, and when the replication lag is 0, promote it as its own DB cluster

  • can take time and cost $

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External PostgreSQL to Aurora PostgreSQL

• Create a backup and put it in Amazon S3
• Import it using the aws_s3 Aurora extension

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DMS: up and running

• Use DMS if both databases are up and running
  • do continious replication between 2 db.

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